Liquid-tight swivel coupler for electrical conduit

ABSTRACT

A swivel coupler for connecting a pair of rigid electrical conduits especially in a confined space, includes a tubular body member with an inner sleeve of rigid plastic material, which protrudes slightly beyond the ends of the body. A pair of nuts are slidably mounted on the outer peripheral surface of the tubular body between outwardly directed radial flanges adjacent opposite ends of the body and which thread a corresponding conduit. A method of fabricating the coupling is to reverse opposite body ends 180* to abut the outer peripheral surface of the body, have one end with an outside diameter smaller than the inside diameter of the nuts, position the nuts back to back on the body, and then enlarge the reduced end of the body to its normal diameter.

United States Patent 1 1 Eidelberg et a1.

[54] LIQUID-TIGHT SWIVEL COUPLER FOR ELECTRICAL CONDUIT Inventors: Jonah Eidelberg, Huntington Sta-- tion; Thomas Mooney, Mt. Sinai; John J. Brett, Syosset, all of NY.

Electrical Fittings Corporation, East Farmingdale, NY.

Filed: Nov. 18, 1970 Appl. No.: 90,496

Assignee:

US. Cl. ..174/84 S, 174/65 R, 174/78, 174/83, 285/55, 285/110, 285/156, 285/177, 285/354 Int. Cl ..H02g 3/06, F16] 19/00 Field of Search ..285/55, 110, 354, 382, 158, 285/247, 177, 161, 238; 174/65 R, 65 SS, 78, 83, 84 S References Cited UNITED STATES PATENTS Whitehead ..285/55 X Ellis ..285/55 X Crawley ..285/354 X Mason ..285/177 X Dorman ..285/247 X [111 3,710,911 [451 Jan. 16, 1973 2,522,194 9/1950 Richardson ,.285/382 X 3,494,643 2/1970 3,493,672 2/1970 2,947,800 8/1960 Badeau et al. ..174/65 R FOREIGN PATENTS OR APPLICATIONS 66,788 1913 Switzerland ..285/354 Primary ExaminerThomas F. Callaghan Attorney-Howard C. Miskin 57 ABSTRACT A swivel coupler for connecting a pair of rigid electrical conduits especially in a confined space, includes a tubular body member with an inner sleeve of rigid plastic material, which protrudes slightly beyond the ends of the body. A pair of nuts are slidably mounted on the outer peripheral surface of the tubular body between outwardly directed radial flanges adjacent opposite ends of the body and which thread a corresponding conduit. A method of fabricating the coupling is to reverse opposite body ends 180 to abut the outer peripheral surface of the body, have one end with an outside diameter smaller than the inside 1 diameter of the nuts,-position the nuts back to back on the body, and then enlarge the reduced end of the body to its normal diameter.

10 Claims, 11 Drawing Figures PATENTEUJAN 16 I973 3,710.91 1

SHEET 1 UF 3 FIG./

! 22 IEUIIIIIII HQ 2 z- Z8 1; mm 36 INVENTORS JONAH EIDELBERG THOMAS MOONEY y JOHN J. BRETT Hwn M PATENTEU JAN 1 6 I973 SHEET 2 BF 3 I\'\I-I\'I'ORS JONAH EIDELBERG THOMAS MOONEY PATENTEUJAHIS 1915 3,710,911

sum 3 nr 3 INWIYTORS JONAH EIDELBERG THOMAS MOONEY JOHN J. BRETT LIQUID-TIGHT SWIVEL COUPLER FOR ELECTRICAL CONDUIT The present invention relates to an electrical coupling or a connector for attachment to electrical conduit and in particular for a coupling used in attaching a pair of conduits in a confined space, where there is substantially no play in the conduit, and making a liquid-tight connection with a secure grounded installation, and which allows ready removal or opening of the installation whenever needed.

Heretofore, when conduit, especially rigid conduit, was installed in a confined space, which allowed no play in the conduit, i.e., no movement of the conduit, it was difficult to install, or, if necessary for whatever the reason, to reopen the connection and replace a section of conduit or to gain entrance to the conduit. Ad-

ditionally, in many cases a good liquid tight seal was necessary, if the coupling connection was made in any location where there was moisture in the air or liquid splashing on the conduit, which could enter the conduit by the smallest opening in the coupling connection if it was not perfectly liquid-tight. Any moisture condensed and trapped in the conduit enhances corrosion and makes for poor electrical connection and possible shorts. Additionally, a good ground connection between the connected conduits was necessary. Oftentimes in the past, a coupling, which made a good liquidtight seal made a poor ground connection and vice versa. I-Ieretofore, to provide a good ground and a liquidtight connection as well as connect conduit in a confined space, normally required a three-part connection which was expensive, increased the cost of installation, and required a separate fitting of some type. Also, stocking of the various parts of these separate fittings became an inventory problem besides the propensity of the separate fittings to become separated.

Therefore, it is a principal object of the present invention to provide a coupling for electrical conduits for extremely tight space installations which is simple to use and which provides a secure liquid-tight installation with proper grounding.

A further object of the present invention is to provide a coupling for electrical conduits which can be attached to and can clamp the conduits by various means.

Another object of the present invention is to provide an electrical coupling for conduits which allows interconnection of a plurality of conduits, even at angles to produce a secure liquid-tight installation in even a confined area.

A still further object of the present invention is to provide a coupling for electrical conduits, which could be of different diameters, and which is simple to fabricate, allows no separation of parts to avoid any loss of parts in the field, and is inexpensive to produce.

Still another object of the present invention is to provide a liquid-tight swivel coupling for electrical conduit which does not require rotation of either the conduit or coupling body, and which is simple 'to use and install and remove and re-install as needed.

Further objects and advantages will become apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. I is a general perspective view of a coupling made in accordance with the present invention connecting a pair of rigid conduits;

FIG. 2 is an enlarged cross-sectional view taken along line 2--2 of FIG. I;

FIG. 3 is an elevational cross-sectional view of the coupling shown in FIG. 2;

FIG. 4 is an elevational view, partially in section, of another form of the coupling for connecting different size conduits;

FIG. 5 is an elevational view, partially in section, of another form of the coupling connecting a plurality of conduits; 7

FIG. 6 is an elevational cross-sectional view of a body partly formed; 2

FIG. 7 is a vertical section through a set of dies, which may be used in a power press, showing the operation thereof for carrying out a step in the method of fabricating the coupling;

FIG. 8 is an enlarged fragmentary elevational view of a step in the fabrication of a further embodiment illustrating the bottom die preparatory to perform the expanding operation, and the upper die after the expanding operation has occurred;

FIG. 9 is a view like FIG. 8 and shows a fragmentary cross-sectional elevational view of a completed further embodiment of a coupling;

FIG. 10 is a fragmentary elevational view showing the coupling of FIG. 9 in operative position; and

FIG. 11 is a fragmentary elevational cross-sectional view showing a still further embodiment of the present invention.

In the form of the invention shown in FIGS. 1-3, an electrical coupling 20 incorporating the invention has a hollow tubular body 22 for connecting a pair of conduits 24 and 26 at opposite open ends. Body 22 has a through bore between its ends. Rotatably and slidably mounted about the outer peripheral surface of body 22 are a pair of nuts 28 and 30 back to back and their open ends facing towards corresponding ends of body 22. As seen best in FIGS. 2 and 3 the opposite ends of body 22 are rolled over exteriorly and juxtapositioned to the outer peripheral surface of body 22 to form flanges 32 and 34, respectively. Flanges 32 and 34 cooperatively engage corresponding inwardly directed nut flanges 36 and 38, respectively. As seen best in FIG. 3, nuts 36 and 38 are back to back on body 22. Nuts 28 and 30 have internal peripheral surfaces threaded, as indicated at 40 and 42, respectively, to mate with corresponding threads about the outer surface of conduits 24 and 26, respectively. Nuts 28 and 30 are freely rotatable and slidable on body 22 between flanges 32 and 34. It is important that body 22 have sufficient distance between flanges 32 and 34 so that when nuts 28 and 30 abut at one end of body 22, the end of the other nut does not project beyond the other end of body 22. This allows the full unthreading of at least one of the nuts with no part of the nut extending beyond the body end.

Tightly abutting the inner peripheral surface adjacent one end of body 22 is a resilient sleeve 44. Advantageously, sleeve 44 is force fitted into body 22 and retained by friction. Sleeve 44 has a radially outwardly directed portion 46, which is advantageously thicker than the remaining skirt portion, which is positioned within the bore of body 22. A portion of thick end 46 of sleeve 44 extends slightly beyond the edge of body 22. In a similar manner, a second resilient sleeve 48 is fitted into the opposite end of body 22 and similarly has a thick end 50 which extends slightly beyond the other edge of body 22. The facing ends of sleeves 44 and' '48 are preferably spaced apart, but longer sleeves are used.

In use body 22 is shown mounted between facing ends of rigid conduits 24 and 26, which as shown have threaded ends for mating with its corresponding nut on coupling 20. Nut 28 is threaded on the mating threaded portion of conduit 24. Nut 28 is tightened forcing conduit end 25 of conduit 24 toward the facing end of body 22. As seen best in FIG. 2, conduit end 25 engages the projecting end 46 of sleeve 44, and as nut 28 is further tightened, conduit end 25 deforms and flexes sleeve end 46 until conduit ends 25 engages the facing end of body 22 making a metal-to-metal contact. The deforming and flexing of portion 46 of sleeve 44 urges sleeve 44 tightly against conduit end 25 and forms a tight seal about conduit 24, regardless of any surface irregularities or dirt or slight misalignment.

In a similar manner, conduit 26 is positioned abutting the opposite end of body 22 and nut 30 is threaded about the mating threaded surface of conduit 26 forcing conduit end 27 into engagement with thickened resilient sleeve end 50 of sleeve 48, until conduit end 27 abuts the facing end of body 22, making a metal-tometal contact as well as deforming sleeve end 50 to make a further tight seal about conduit end 27.

As is evident from FIGS. 1 and 2, conduits 24 and 26 being coupled can just fit the available space with no rotation of the conduit necessary. The conduits are illustrated as being immovable and passing through walls 52 and 54, respectively. As shown, conduit 26 is a 90 elbow which can not be rotated, to thread it on a coupling since wall 54 prevents rotation. With this type of installation, only a 3-part coupling could have been used. Coupling allows easy assembly, and if necessary, disassembly with the sole threading rotation being nuts mountedon the body of thecoupling. Since neither the body of the coupling nor conduits need be rotated during installation, the seal is made solely by relative axial movement of the conduit and coupling body, thereby lessening the likelihood of scoring-or cutting the sealing member. Even with the facing ends of the clamped conduits 24 and 26 being in close abutting relation with body 22, and the conduits being fixed during installation with the present invention, it is a relatively simple matter to remove'the coupling if need arises without disturbing the conduit. To accomplish this, the space between flanges 32 and 34 on body 22 must be sufficient so that when the flanges of nuts 28 and 30 abut, the nuts are entirely intennediate of the ends of body 22; so that body 22 can be forced between the facing ends of conduits 24 and 26, if

necessary.

As is evident, in use there is no need to bend or deform the conduit to assemble even in tight areas.

An embodiment that couples two'differe'nt diameter conduits is illustrated in FIG. 4, where a hollow body member 52 has a larger inner diameter at one end, indicated at 54 and a smaller inner diameter at theother end, indicated at 56. As shown portions 54 and 56 are interconnected by a center portion "58 where the change in diameter occurs. Center portion 58 has an outwardly directed rib which restricts the movement of nuts 60 and 62. The opposite ends of body member52 could be closer if openings 66, 68 and70 communicating with the internal bore 72. While openings 66 and 68 are shown axially aligned and opening 70 being transverse thereto, opening 70 could be positioned at anyangle to the axis of body 64, and similarly opening 68 could be positioned at an angle to opening 66. With the construction of the coupling illustrated in FIG. 5, connections to various conduits, aligned at various angles with each other can easily be made since neither the coupling nor the conduits are rotated, but only the rotatable nut' mounted on the body.

\ While the flexible sleeves are not shown positioned within the bore 72, they could if desired.

In use, the coupling illustrated in FIG. 5 is assembled on various conduits in a manner described above with respectto the embodiments shown in FIGS. 1-3. Also, while openings 66, 68 and 70 are shown being all substantially'equal in diameter, they could vary in diameter in a manner similar to that shown in FIG. 4 to couple various sized conduits. Also, more than three openings can be accommodated in the body.

In carrying out the improved method of making and assembling a coupling in accordance with the present invention, reference is made to FIGS. 6 and 7 where a hollow tubular body member 74 has a passageway theretlirough, and is provided preferably of a suitable ductile material, for example a steel, which may or may not be heat-treatable or hardenable. The opposite ends of body member 74 are rolled over to form flanges and against which the nut flanges rest. One of these ends has a larger outer diameter than the other end, which could be accomplished in many ways, well known in the art, so as to allow positioning of the nuts on the body. Then the reduced or smaller end is expanded to its finished size, thereby permanently positioning of the nuts on the body. Then the reduced or smaller end is expanded to its finished size, thereby permanently positioning the nuts on the tubular body. A rigid plastic sleeve may then be inserted into the interior passageway of the tubular member 74.

The tubular member 74 illustrated in FIG. 6 can be formed in a variety of ways well known in the art. The ends of the tube, including one end 76 reduced in diameter can be fabricated using well known techniques in the art, such as a sequential forming operation and then a squeezing operation.

Body member 74 has bent over ends to form flanges 78 and 80 at opposite ends. Reduced'end 76 is smaller in diameter than the inner diameter of the nuts to be mounted about the outer peripheral surface of body member 74,and the end opposite end 76 provides an interference fit with the mating flange of the nuts, As illustrated best in FIG. 7, nuts '82 and 84 are slid onto body member 74 over the reduced end 76 and positioned in back-to-back relation. Reduced end 76 has an outer diameter just'sufficient to allow nut flanges 86 and 88 to pass. Nut flanges 86 and 88 abut.

Once nuts 82 and 84 are positioned on body member 74, it is advantageously expanded in a die assembly illustrated in FIG. 7. The die assembly is adapted for mounting in 'a suitable power press (not shown) for operation thereby and comprises a bottom die member 90 having an inner flange or a step 92. Die member 90 has a bore 94 which has an inner diameter substantially equal to slidably receive the outer diameter of nuts 82 and 84. The lowermost edge of the bottom nut illustrated as 84 rests on step 92. Axially movable within bore 94 is a reciprocating punch or finger 96 having a reduced diameter end portion 98. The outer diameter of punch 96 is substantially the same as the desired finished inner diameter of member 74. Punch 96 slidably fits within the bore of the larger diameter end of tubular member 74 and is larger than the inner diameter of reduced end portion 76. As illustrated in FIG. 7, the lower end of member 74 is the reduced portion 76. Nuts 82 and 84 are positioned within bore 94 of die 90 as shown with flanges 86 and 88 abutting. Member 74 is slid into bore 94 with reduced end 76 downwardly extending and body flange 78 rests on uppermost nut flange 86. Punch 96 extends into bore 94 and then into the bore of member 74. Smaller punch end 98 is centered within the bore of member 74 and then continues its movement into bore 94 and expands sleeve 74 outwardly to complete the expanding operation of the reduced end 76 of the body member 74. The movement of punch 96 forces the reduced end 98 and the remainder of punch 96 through the opening of member 74 and is carried far enough through bore 94 to pass punch 96 through reduced portion 76 of member 74 so as to expand member 74 to its finished diameter, so that body flange 80 interferes with nut flange 88. After this expanding operation is completed the tube and nuts are removed from punch 96 and the coupling is almost ready to be used.

'The next step is the insertion of resilient sleeve 44 and 48 into the bore of tubular member 74 from opposite ends if so desired. Because of the resiliency of sleeve 44 and 48 these are press-fitted into the ends.

The completed coupling is illustrated in FIG. 3 and in use in FIG. 2.

If desired, one body flange could be formed at a time to allow placement of the nuts before the second end is turned or the nuts placed on the body before the ends are turned.

A further embodiment is illustrated in FIG. 8, which illustrates a uniform diameter tube 102 supported in a die assembly having nuts 104 and 106 positioned and held adjacent opposite ends. Nuts 104 and 106 have flanges 108 and 110, respectively, with tapered surfaces 112. Moving into the bore of tube 102 from opposite ends are plungers 114 and 115, each having tapered ends 116. As shown, plunger 115 is just beginning to move into the bore of tube 102. Continued relative movement of plunger 114 forces the ends of tube 102 against tapered surface 112 of the nut flange, which is illustrated with respect to plunger I14 and is flush against tapered surface 112 of nut flange 110. The outward flared opposite ends of tube 102 hold nuts 104 and 106 in position, which is illustrated in FIG. l0. Resilient sleeves "8 are positioned within the interior ofv the bore of tube I02. Sleeves 118 have thickened ends 120 which project slightly beyond the flared ends of tube 102, which is shown in FIG. 10.

In use, nuts 104 and 106 are tightened on mating threaded ends of conduits 122 until ends 122 deflect thickened ends 120 of sleeves 118, and until conduit ends 122 engage their corresponding flared ends of tube 102, which is illustrated in FIG. 11. This makes a liquid-tight seal, as discussed above with respect to FIG. 2.

A still further embodiment is illustrated in FIG. 12, in which the ends of tube 124 are bent over interiorly, as illustrated at 126. Nuts 128 are mounted on tube 124 in the manner discussed above, and the ends flared outwardly. In a similar manner, resilient sleeves 130 are positioned interiorl'y of tube 124.

Also while a pair of resilient sleeves were shown positioned within the bore of tube 124, a single unit may be used. The flexibility of the sleeve allows the insertion of the unitary sleeve. While the use of flexible sleeve interiorly of the coupling member provides a fluid-tight seal with the conduit and coupling body and is essential where the coupling is being used in a hazardous location, such as inflammable or explosive atmospheres, making a fluid-tight coupling is not essential in some in stances. The resilient sleeves do not have to be used, and metal-to-metal contact is made between the coupling body and the conduit.

Resilient sleeves shown are preferably molded in the desired configuration or can be extruded in place by applying a selected force. Advantageously, sleeves 30 and 34 are made of a resilient plastic, such as nylon, polypropylene, Teflon," or elastomers, or the like, or

- ductile metals, such as lead or soft copper can be used.

It will be seen from the above that in all forms of the coupling, the nuts are positioned during the fabrication. Even if the conduit enddoes not abut the metal body of the tubular sleeve member, a liquid-tight seal is formed and the ground can be made via the nuts used. In the present invention, both a metal-.to-metal contact and aplastic-to-metal seal can be made.

The deforming of the thicker section of the resilient sleeve during assembly provides a slight bending or flexing about the thinner section of the sleeve, which more securely holds the sleeve in the body bore and makes a fluid-tight seal in the interior of the bore of the body member.

While a preferred embodiment of this invention has been specifically disclosed, it is understood that this invention is not limited thereto, since many variations will be readily apparent to one skilled in the art, and the invention is to be limited only by the terms of the following claims.

What I claim is:

l. A coupling assembly comprising a pair of spaced metal electrical "conduits having end walls, and a coupling including a rigid tubular body having outwardly projecting flanges at opposite ends and a bore passing therethrough, said ends being generally axially aligned and in end-to-end engagement with corresponding conduit walls, a resilient sleeve fixedly received within and abutting the surface defining the bore at each end of said tubular body, each sleeve projecting beyond the end of said body and engaging the inside bore wall at the end of a respective conduit wall, conduit clamping means axiallymovably and rotatably positioned on the outer surface at opposite ends of said tubular'body removably clamping said tubular body to the corresponding ends of said conduits for maintaining said body, conduits and sleeves in assembled sealing relation, and clamp retaining means cooperating with said body flanges for retaining said clamping means on said body. u

2. A coupling as in claim 1, wherein said sleeve has a thicker end portion which is radially aligned with said .body flange and protrudes beyond the end of said tubular body.

3. A couplingtas in claim 1, wherein one of said ends of said tubular body being ofa reduced diameter than the other end for mating with a corresponding reduced diameter conduit.

4. A coupling as in claim 1, wherein said flanges on said body are .rolled over portions at opposite ends abutting the exterior surface of said body.

5. A coupling as in claim 1, wherein said body flange is a rolled over portion abutting the interior peripheral surface at opposite ends, and said body ends being flared radially outwardly to .form said flanges.

6. A coupling as in claim 1, wherein said coupling means are nuts and rotatably mounted on said body,

' and said body flanges are outwardly flared body ends. a

7. A coupling as in claim 1 wherein said body flanges are spaced apart a distance at least equal to the length thickness'of one of said nut flanges and the length of the other nut. v 9. A coupling for attachment to a pair of spaced tubular electrical conduits having end walls comprising: a'

rigid tubular body having flanges at opposite ends and a bore passing therethrough, said ends being generally axially aligned with said conduit walls and adapted to engage the conduit end walls when assembled thereto to provide metal-tometal contact and an electrical ground, a pair of nuts in back-to-back relation slidably and rotatably mounted about the outer surface of said body having .an interiorly directed flange which cooperates with said body flange to prevent displacement of the body and to position said nut during assembly, said body flanges being spaced apart a distance at least equal to the length of one of said nuts and the thickness of the flange on the other of said nuts. and a resilient sleeve telescoping each end of said tubular body and in moisture tight engagement therewith, said sleeve including a portion projecting beyond the end of 'said body and having an outwardly bulging outer peripheral end border whose maximum diameter is I greater than the inside diameter of said conduit and of one of said coupling members and the thickness of said clamp retaining means. I

8.- A coupling as in claim 3, wherein said body flanges are spaced apart a distance at least equal -to the 

1. A coupling assembly comprising a pair of spaced metal electrical conduits having end walls, and a coupling including a rigid tubular body having outwardly projecting flanges at opposite ends and a bore passing therethrough, said ends being generally axially aligned and in end-to-end engagement with corresponding conduit walls, a resilient sleeve fixedly received within and abutting the surface defining the bore at each end of said tubular body, each sleeve projecting beyond the end of said body and engaging the inside bore wall at the end of a respective conduit wall, conduit clamping means axially movably and rotatably positioned on the outer surface at opposite ends of said tubular body removably clamping said tubular body to the corresponding ends of said conduits for maintaining said body, conduits and sleeves in assembled sealing relation, and clamp retaining means cooperating with said body flanges for retaining said clamping means on said body.
 2. A coupling as in claim 1, wherein said sleeve has a thicker end portion which is radially aligned with said body flange and protrudes beyond the end of said tubular body.
 3. A coupling as in claim 1, wherein one of said ends of said tubular body being of a reduced diameter than the other end for mating with a corresponding reduced diameter conduit.
 4. A coupling as in claim 1, wherein said flanges on said body are rolled over portions at opposite ends abutting the exterior surface of said body.
 5. A coupling as in claim 1, wherein said body flange is a rolled over portion abutting the interior peripheral surface at opposite ends, and said body ends being flared radially outwardly to form said flanges.
 6. A coupling as in claim 1, wherein said coupling means are nuts and rotatably mounted on said body, and said body flanges are outwardly flared body ends.
 7. A coupling as in claim 1, wherein said body flanges are spaced apart a distance at least equal to the length of one of said coupling members and the thickness of said clamp retaining means.
 8. A coupling as in claim 3, wherein said body flanges are spaced apart a distance at least equal to the thickness of one of said nut flanges and the length of the other nut.
 9. A coupling for attachment to a pair of spaced tubular electrical conduits having end walls comprising: a rigid tubular body having flanges at opposite ends and a bore passing therethrough, said ends being generally axially aligned with said conduit walls and adapted to engage the conduit end walls when assembled thereto to provide metal-to- metal contact and an electrical ground, a pair of nuts in back-to-back relation slidably and rotatably mounted about the outer surface of said body having an interiorly directed flange which cooperates with said body flange To prevent displacement of the body and to position said nut during assembly, said body flanges being spaced apart a distance at least equal to the length of one of said nuts and the thickness of the flange on the other of said nuts, and a resilient sleeve telescoping each end of said tubular body and in moisture tight engagement therewith, said sleeve including a portion projecting beyond the end of said body and having an outwardly bulging outer peripheral end border whose maximum diameter is greater than the inside diameter of said conduit and whose end is rounded and in its relaxed state has a diameter greater than the inside diameter of said conduit, said end border adapted to engage the inside bore of a corresponding conduit.
 10. The coupling of claim 9, said flanges being formed by outwardly directed rolled over ends of said body, said rolled over ends being substantially parallel to the exterior surface of said body adjacent said ends. 